Patent Document 1 discloses a temperature control device which controls a temperature of a heating plate having a semiconductor wafer mounted thereon. In the temperature control device, the heating plate is heated by a heater, so that the semiconductor wafer mounted on the heating plate is heated. Then, the temperature control device controls the heating operation of the heater so that the temperature of the heating plate becomes a target temperature.
Incidentally, in the temperature control device disclosed in Patent Document 1, when the heating plate is influenced by disturbance, the temperature of the heating plate becomes higher or lower than the target temperature (hereinafter, the target temperature will be referred to as an ‘initial target temperature’). That is, when the heating plate is influenced by disturbance, the temperature of the heating plate changes.
Here, if the target temperature of the heating plate temporarily becomes lower than the initial target temperature when the temperature of the heating plate is about to become higher than the initial target temperature, the amount of heat given from the heater to the heating plate decreases, thereby suppressing the temperature of the heating plate from becoming higher than the initial target temperature. In contrast, if the target temperature of the heating plate temporarily becomes higher than the initial target temperature when the temperature of the heating plate is about to become lower than the initial target temperature, the amount of heat given from the heater to the heating plate increases, thereby suppressing the temperature of the heating plate from becoming lower than the initial target temperature. Accordingly, when the target temperature of the heating plate changes in a manner opposite to a change in temperature which may occur in the case where the target temperature of the heating plate is maintained at the initial target temperature when the heating plate is influenced by disturbance, the temperature of the heating plate is maintained at the initial target temperature even when the heating plate is influenced by disturbance.
Therefore, in the device disclosed in Patent Document 1, disturbance is forcedly given to the heating plate in a state where the temperature of the heating plate is controlled at the initial target temperature, and the temperature change pattern of the heating plate at this time is measured. Then, the temperature change pattern opposite to the temperature change pattern of the heating plate at this time is acquired as the target temperature change pattern of the heating plate when the heating plate is influenced by the disturbance. Then, when the heating plate is influenced by the disturbance similar to the above-described disturbance, the target temperature of the heating plate is changed in accordance with the acquired target temperature change pattern, and the temperature of the heating plate is maintained at the initial target temperature.
In this way, Patent Document 1 discloses a concept in which the temperature of the heating plate is maintained at the initial target temperature by changing the target temperature of the heating plate itself in accordance with the target temperature change pattern when the heating plate is influenced by disturbance.